octhomasad
Hi guys. A newbie here. I have a generac 4456-3 installed in 2004 running on L.P. I have had a few problems over the years (rear cylinder not firing for a min. or two on startup,always shuts down 1n 15 seconds on startup but then restarts and runs fine (only in warmer temps.) backfire on startup which i can stop if i turn rear adjustment screw cw.(every 3 months it will start to backfire again and i have to turn screw cw some more. I have purchased a new regulator (0d8631) because i think all these problems are related to regulator. Any suggestions for pre-adjusting screws before i install.
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techntrek
Your issue with shutting down on startup sounds like mine, see my thread here - very recently updated so shouldn't be hard to find.
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bronco
screws should be turned out 2.5 turns from seat. Please check gas pressure you should have between 11 -14 inches of W.C. are the screws backing themselves out or in?
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octhomasad
No screws are not moving by themselves. It is just the rear one i have to turn in cw every few months. This is why i suspect the problem is in one half of regulator. (gas pressure is correct)
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Scotty306134
Since the engine is only running on one cyl when it's cold and backfires on starting, I'm suspicious You have a sticking intake valve. I'd recommend taking a compression test on the cold engine.
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octhomasad
That was about 3 years ago when it was running on one cyl. When i turned rear screw in cw a bit, problem went away. I did do a compression check at that time and it was ok. the backfire goes away after turning rear screw cw a bit. I have done this about 3 times and I am now up against factory limit pin on rear screw.
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bronco
We will assume that you have converted this to propane so next thing you need to do is pull the pins out the regulator and then adjust your regulator with the engine running to the highest RPM or frequency. Once you have adjusted your regulator you want to turn your screws in approximately 1/2 turn clockwise and your regulator should be set up and engine should run just fine. I would like to know what your incoming gas pressure is to your unit it should be 11 to 14 inches of water column and then I would also be nice to know what the gas pressure is when the generator is running.
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octhomasad
Pressure was checked and is ok. I might add that it runs great when running. (Ran for 70 hours during last power outage in nov.). I only stopped it twice to check oil. I am still thinking something is sticking in regulator on startup. I will not put in new regulator untill all this snow melts and temp. warms up !!!!!!!! Thanks everyone for all the input.
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ohmslaw
Have you ever adjusted the valves?
Tim
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octhomasad
Valves are adjusted correctly.
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octhomasad
octhomasad;8306 wrote:
Hi guys. A newbie here. I have a generac 4456-3 installed in 2004 running on L.P. I have had a few problems over the years (rear cylinder not firing for a min. or two on startup,always shuts down 1n 15 seconds on startup but then restarts and runs fine (only in warmer temps.) backfire on startup which i can stop if i turn rear adjustment screw cw.(every 3 months it will start to backfire again and i have to turn screw cw some more. I have purchased a new regulator (0d8631) because i think all these problems are related to regulator. Any suggestions for pre-adjusting screws before i install.


Just a little update. All these problems went away when i installed a new regulator. I suspect selonoid was sticking or regulator seal on one side was sticking, or both.
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